Model Nine
| Brand | Polk Audio |
| Function | Speaker |
| Produced | 1973-1975 |
| Country | United States |
| Model ID | Model 9 |
| Form Factor | Floorstanding |
| Signal Path | Passive Hardware |
| Dimensions | 26.7 × 85.1 × 22.9 cm (W × H × D) |
| Weight | 40lbs |
| Frequency Response | 47Hz-27kHz ±2dB |
| Treble | 3" Horn-Loaded Piezo |
| Midrange (Front) | 4.5" Paper Cone |
| Bass (Rear) | 4.5" Paper Cone (x3) |
| Passive Radiator | 8" Paper Cone |
| Impedance (Nominal) | 8Ω |
| Crossover Frequencies | 180Hz, 3.5kHz |
| Power Handling | 100W |
| Enclosure Type | Passive Radiator |
| Finish | Walnut |
| MSRP (1974) | $165 |
| Notes | Crossoverless design, mechanical limitations and innate inductance of woofers and capacitance of piezo provide crossover points. |